Operating mechanism for machine guns



F. l. RATAICZAK 2,458,028

OPERATING MECHANISM FOR MACHINE GUNS I Jan. 4,1949.

4 Sheets-Sheet 1 Original Filed May 19, 1944 Jan. 4, 1949. F. I.RATAICZAK OPERATING MECHANISM FOR MACHINE GUNS 4 Sheets-Sheet 2 OriginalFiled Mayl9, 1944 H z: y I.

wuu NR 4 I v v Non Jan. 4, 1949. F. 1. RATAICZAK OPERATING MECHANISM FORMACHINE GUNS Original Filed May 19, 1944 4 Sheets-Sheet 3 Jan, 4, 1949.l. RATAICZAK OPERATING MECHANISM FOR MACHINE GUNS v Original Filed Mayis, 1944 4 Sheets-Sheet 4 INVENTOR.

BY M

Patented Jan. 4, 1949 OPERATING MECHANISM FOR MACHINE GUNS Francis I.Rataiczak, Dayton, Ohio, assignor to General Motors Corporation, Dayton,Ohio, 2!. I corporation of Delaware Original application May 19, 1944,Serial No.

536,229. Divided and this application November 23, 1945, Serial No.630,199

4 Claims.

This invention relates to ordnance and more particularly to an improvedmachine gun construction.

This application is a division of my application S. N. 536,229 filed May19, 1944.

One object of this invention is to provide a low cost machine guncapable of firing high powered (SO-caliber ammunition.

Another object of this invention is to improve upon the receiverconstruction so as to make a it) feed mechanism 58 to direct the feedbelt and strong lightweight receiver suitable for mass prothe cartridgescarried thereby into the breech duction. housing 50. I p

Another object of this invention is to provide 7 Reference numeral 64designates generally an a a gun in which the parts are adapted to massproadapter which is used. for mounting the gun and duction and in whichthe parts of one gun are which incorporates a standard bufferarrangereadily interchangeable with the parts of other ment, the detailsof which form no part of niy inguns. vention and will not be describedin detail. The A further object of this invention is to provide cover 54may be latched in its downward position an improved mechanism for handcooking the by the cover latch 66 (Fig.4) which engages the gun. coverlatch strike 68 carried bythe breech hous- More particularly it is anobject of this invening 50. The latch 65 is operated by means of thetion to provide a means for hand cocking the handle 10 (Figs, 1,2 and 3)which is arranged as gun which makes it possible to hold the bolt inshown. The latch 6611s no'rmally'held in latch" any desired position.ing engagement by the "spring 12. Inasmuch as Further objects andadvantages of the present the details of the'latch form no part ofthisininvention will be apparent from the following dc vention, furtherdescription of the latch .mech-' scription, reference being bad to theaccompanyanis'm is believedto beunnecessary. v ing drawings, wherein apreferred form of t The ec h s g 50 is made up in a novel presentinvention is clearly shown. manner in that it comprises stamped sheet,metal In the drawings: elements to which the rear end piece I36 is 1 isa side elevational view of a gun emattached. The rear end of,th'elbarrel 52 is probodyingmy invention; vided With suitableinterlocking locks 80 which Fig. 2 is a side elevational view similar toFig. lock the barrel in fixed relationship to the breech 1 but showingthe breech cover raised; ring 82'. The breechring 82.'is provided with aFig. 3is atop view of the gun; if; projecting key portion 96 at itslower front end Fig. 4 is a fragmentary sectional view on an whichslides within a keyway 98 provided in the enlarged scale showing therear portion of the barrel extension-84 whereb'y'thebreech, ring is gun;allowed to reciprocate within the. barrel extension Fig. 5 supplementsFig. 4 and shows the con-' but is not permitted to rotate relative thebarrel s'truction of the front portion of thegun; extension. The barrelextension Bllf'i provided Fig. 6 is a top view of the rear portion ofthe with a locking'stud [08' whichieng'ag'es'. a slot I I0 bolt;provided in the front end of thereceiverlfill. Fig. 7 is a side view ofthe bolt portion shown in The relatively heavy end piece."l3.6 serves toFig. 6; I reinforce the lighter weightjstampings at the Fig. 8 is a topview of the bolt head showing one end thereof and also provides a rigid.mounting of the side rollers in section; member which may be'machin'edthe same as if Fig. 9 is a side view of the bolt head shown in theentire breech housing were made from a large Fig.8; piece of heavyhammer.

Fig. 10 is an elevational view of the bolt head The breech housingserves togu'i'de the bolt as cam; and sembly generallydesignatedbythereference nu- Flgill is a vertical sectional view which shows meralI50. .The rear 'end' piece. .136 is suitably the relationship of theshell feeding mechanism machined so' 'as 'toserveas th'efhous'" -f'o'rthel to thecover and the cam tube. bolt buffer. .niechar ism. generallydesignated ilby Referring now to Figs, 1, 2 and 3 of the drawthereference'numeral 152 andfbes'tshown'i'nIF i-n'g,'-'-rference numerals50 and '52 designate the 4. Since the boltbufif'er mechanismwhichcambreech housing or receiver and barrel respective ly of a -caliberrapid fire machin gun. Reference numeral 54 designates generally thecover for the breech housing which is pivotally secured to the breechhousing at 56. A belt feed mechanism 58 is removably secured to :thecover member 54 in a manner to be explained more fully hereinafter. Thefeedway 69 which is'secured to the breech housing 50 cooperates Withthebelt prises a plurality of concentric springs is of standardconstruction and since the details thereof form no part of thisinvention, other than the manner in which the element I36 is formed andheld in place, the bolt buffer mechanism will not be described greaterdetail, The bolt assembly comprises a main bolt body portion I54 and abolt head portion I55 which includes a shank I58 which telescopes intothe bolt head cam element I66 carried within the recess I60 provided inthe forward portion of the main bolt body I54.

A firing pin I is carried by the main bolt body I54 as shown andprojects through a central aperture I12 provided in the bolt head I56.The lower side of the bolt head I56 is recessed as best shown in Fig. 4,for the reception of the shell extracting element I14 which is mountedon the pivot I16 and which is biased into shell engaging position by acompression spring I18. A shell ejector I80 is pivotally supported bythe bolt head I56 and serves the usual purpose of a shell ejector.

The bolt head I56 is mounted for partial rotation relative to the mainbody portion I54 as will be explained more fully hereinafter. As bestshown in Fig. 8, the bolt head I56 is provided with interrupted screwsegments I82 which are adapted to interlock with complementaryinterrupted screw segments I84 provided within the breech ring 82 uponapproximately a quarter turn of the bolt head. The bolt assembly I50 maybe held in the rear position by the sear I86 which is normally biasedinto bolt latching position by the compression spring I88 arranged asshown in Fig. 4. Upon release of the bolt assembly by the sear I86, thebolt assembly moves forward until the bolt head rollers close againstthe cam surfaces I93 of the breech ring 82 at which time the bolt headstops and the rear portion of the bolt continues to move forward. Therollers I9l of the bolt head strike the cam surfaces I93 on the breechring 82 so as to initiate rotation of the bolt head I56 just before thebolt head reaches its forward position. The continued forward move-.ment of the rear portion of the bolt causes the cam surfaces I90 thereonto engage the projecting rollers I9I of the bolt head I56 so as tofurther rotate the bolt head. Rotation of the bolt head causes theinterrupted screw segments I82 to interlock with the complementaryinterrupted screw sections I84 provided within the breech ring 82 so asto firmly hold the bolt head in shell firing position during the firingof the shell in accordance with well-known. practice. After the bolthead has been properly locked in shell firing position, the firin pinI10 is carried forward relative to the bolt head into shellfiringposition. Firing of the shell causes recoil of the barrel togetherwith the breech ring and the bolt assem-v bly. Soon after recoil begins.the rollers I9I carried by the projecting shanks I92 of the bolt headwill engage the cam unlocking surfaces 200 provided on the element I02so as. to induce relative rotation between the bolt head and theremainder of the bolt assembly, This relative rotation serves todisengage the interrupt-ed screw segments I82 and I84 whereby the boltassembly may continue to move toward the rear of the breech housing evenafter the recoil energy of the gun barrel has been absorbed by the buffer springs I00, I I8 and I22. In the event that the gun jams with thebolt head locked in its forward position. a pull on the rear portion,154 of the bolt will cause the cam segments I62 on the bolt head. tocooper: ate with the cam slots I64 in the bolt head cam so as to rotatethe bolt head I56. out'of locking 4 engagement with the breech ring 82so as to permit hand cooking of the gun.

As the bolt head I56 moves from the shell firing position towards therear, the ejector cam 202 cams the ejector I into shell ejectingposition. The ejected shells leave the breech housing 50 through thebottom openin I99.

Movement of the bolt assembly I50 operates the cam tube drive bushing204 which is slidably mounted within the cam tube 206 which in turn isrotatably mounted within the cover 54. A bearing stud 205 carried by thecover 54 supports the front end of the tube 206 as shown in Fig. 5. Thecam tube drive bushing 204 is provided with a downwardly projectingportion 208 which is in engagement with an aperture in the lug 209 onthe bolt I50 and is operated thereby. The projection 208 also cooperateswith a spiral cam slot 2 I 0 provided in the wall of the cam tube 206whereby upon reciprocation of the bolt I50, the cam tube 206 is causedto rotate.

One section of the outer wall of the cam tube 206 is provided withexternal gear teeth at 2I2 which mesh with teeth 2I4 provided on thebelt feed slide element 2I6. By virtue of the above describedarrangement, reciprocation of the bolt assembly I50 causes rotation ofthe cam tube 2I2 which in turn operates the belt feed slide element 2I6, in a manner explained more fully in my copending application S. N.536,229 to which reference is hereby made for a detailed description ofthe belt feed mechanism.

A coil spring 2I1 biases the cam tube drive bushing 204 together withthe bolt I54 into the forward position thereof. A hand cockingarrangement is provided which comprises a flexible cable 220 providedwith a hand engaging element 224 on the one end thereof and an element226 on the other end thereof for engaging the cam tube drive bushing204. The ends of the element 226 project through the slots 221 in thetube 229 which is disposed between the springs 2I1 and 228. The coilspring 228 biases the element 226. into its forward position at alltimes. ,In order to hold the bolt assembly I50 in any desired position,a cable clutch or friction brake generally designated by the referencenumeral 230 has been provided which comprises a plurality of clutch jaws232 for gripping and holding the cable 220 in any desired position. Acompression spring 234 normally holds the jaws 232 out of cable grippingposition. In order to move the jaws into cable gripping position it isnecessary to push forward on the cable guide bell 240. Forward movementof the bell 240 overcomes the force of the spring 234 and causes thejaws 232 to be cammed into cable gripping position by the beveledsurface 23I on the clutch housing 233. The jaws 232 remain in the cablegripping position until the cable 220 is pulled outwardly at which timethe jaws momentarily move with the cable until the cam surfaces nolonger force the jaws in gripping engagement with the cable.

In order to remove the belt feed slide assembly from the housing 252 itis necessary to remove the mechanism within the cam tube 206. Thismechanism may be removed by lifting the cover 54 and depressing thelocking plunger 302 so as to make it possible to slide out the mechanismfrom within the cam tube 206. This mechanism bein removed, the cam tubeis free to rotate whereby'the slide assembly 2I6 may be removed from thehousing 252 through the end slot .253.

(Fig.1) 1 .The slot 2|.0 provided in thecam tube may arranged forfeeding the shells into the receiver from the right-hand side or it maybe arranged to feed the shells into the receiver from the lefthand side.When it is desired to change over from right-hand shell feeding toleft-hand shell feeding it is necessary to change the cam tube so as tochange over from a cam tube having a righthand helical slot to a camtube having a lefthand helical slot. It is also necessary to remove thehousing 252 and reverse it end for end so as to move the belt feedingand holdin pawls from the one side of the gun to the other side of theun.

It will be noted that the cover 54 is a sheet metal stamping formed toenclose the cam tube 206 as well as other vital parts of the gun asshown. By virtue of the shape of the cover which comprises both flat androunded portions, the cover is inherently strong, yet lightweight andinexpensive to manufacture.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, as may come within the scope of the claims whichfollow.

What is claimed is as follows:

1. In combination, a gun barrel, a receiver, a breech bolt slidablysupported by said receiver, a guide tube having a slot in the wallthereof, a spring tube drive element disposed within said guide tube andhaving a portion projecting through said slot for engagement by saidbreech bolt, 2. spring within said spring tube urging said bolt forward,manual means extending into said guide tube for engaging said element tomove the breech bolt into gun cocking position, and means for holdingsaid manual means in a partial gun cocking position, said manual meanscomprising a flexible cable and said holding means comprising means forgripping the cable so as to hold the cable in any position desired.

2. In combination, a gun barrel, a receiver, a breech bolt slidablysupported by said receiver, a guide tube having a slot in the wallthereof, a sprin tube drive element disposed within said guide tube andhaving a portion projecting through said slot for engagement by saidbreech bolt, a spring Within said spring tube urging said bolt forward,manual means extending into said guide tube for engaging said element tomove the breech bolt into gun cocking position, and clutch means forholding said manual means in a partial gun cocking position, said manualmeans comprising a flexible element extending into said guide tube andprojecting through one end of said guide tube, said clutch meanscomprising means for engaging said flexible element so as to hold saidflexible element in any desired position.

3. In a machine gun comprising a casing and mechanism within said casingfor automatically effecting feeding, loading, firing and ejection inrapid repetitive succession which mechanism includes a longitudinallyreciprocable breech bolt, the combination with said mechanism of a handoperated cocking cable for hand cocking said breech bolt, spring meansfor biasing said cable out of cocking position, clutch means forengaging said cable for holding the same in any desired position, springmeans for biasing said clutch means out of cable clutching position, andmanual means for positively moving said clutch means into cableclutching position.

4. In combination, a gun barrel, a receiver, a breech bolt slidablysupported by said receiver, a guide tube having a slot in the wallthereof, a spring tube drive element disposed within said guide tube andhaving a portion projecting through said slot for engagement by saidbreech bolt, a spring within said spring tube urging said bolt forward,a guide bell supported at the rear end of said guide tube, manual meansextending into said guide tube for engaging said element to move thebreech bolt into gun cocking position, and clutch means for holding saidmanual means in a partial gun cocking position, said manual meanscomprising a flexible element extending through said guide bell and intosaid guide tube, said clutch means comprising means for engaging saidflexible element so as to hold said flexible element in any desiredposition, said guide bell being arranged relative said clutch means sothat a forward push on said guide bell causes said clutch means to gripsaid flexible element.

FRANCIS I. RATAICZAK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,606,873 Gamache et a1 Nov. 16,1926 1,625,993 Gorton Apr. 26, 1927 1,799,284 Coupland Apr. 7, 19311,897,099 Woody et al Feb. 14, 1933 1,910,121 Muntz May 23, 19332,071,020 Boussel Feb. 16, 1937 2,359,517 Gebeau Oct. 3, 1944 FOREIGNPATENTS Number Country Date 191,038 Switzerland Aug. 2, 1937 OTHERREFERENCES Aberdeen Proving Ground Report. Ordnance Program No. 5826,May 28, 1942. Page 1, and plates 60384, 60397 and 60398.

